Sandra Patricia Rocha, 14, and her sister Erika Muete Rocha, 7, were shot and killed on Tuesday night in the notorious southern Bogota sector of Kennedy.
A reward of over $11,000 (COP20 million) has been posted on flyers all over the area, while police have detained 40 people in order to compare them with two sketches of the assailants that neighbors helped to create.
The first version, which the police appear to be adopting, claims that the girls left their house to make a phone call in a phone booth, but when they returned nobody answered the door for several minutes. They decided to wait for someone to let them in, when two youths approached and shot them. The alleged perpetrators then ran and hid in some nearby bushes.
However, this version conflicts with another explanation of events, which instead states that the murderer was one man. In this version, the murderer apparently followed the sisters to the phone booth and as they returned to their residence he shot them both in the head, just meters from their house.
Although the second version seems like a targeted killing, Bogota Police Commander General Francisco Patiño appeared to dismiss the idea by stating that the family had not received any threats and were not involved in any criminal acts. The family was said to be of a modest background, with the father a flower-seller in a local market.
Patiño did note, however, that Kennedy is an area with serious drug problems and that authorities have moved to allay the fears of residents through an increased security presence.
Kennedy is one of the most dangerous Bogota sectors, with one of the highest murder rates so far in 2011.
According to Europa Press Agency, the crime has outraged Colombian society and unleashed a wave of criticism about the effectiveness of state policies to protect children living in resource-poor areas, where gangs tend to enjoy great power.